Growing pains – adapting orthotic devices to maturing patients

Accommodating growth without compromising fit and function is a challenge for practitioners who prescribe orthotic devices for young patients. Adjustments and add-ons—as well as educating parents about expected changes—can make for smoother transitions.

YouTube is a treasure trove of feel-good videos featuring children walking for the first time with the help of O&P devices. There’s 2-year-old Kayden, 1-year-old Samantha, and 14-year-old Zoe, who lost her left leg below the knee in a jet skiing accident.

But these inspiring images capture only one moment in each child’s journey. What happens down the road as Kayden, Samantha, and Zoe mature and outgrow their devices?

The need to replace an O&P device on a regular basis has its challenges for practitioners, patients, and parents. The patient who has just become accustomed to a device has to start all over. Parents want the best for their children but know these replacements can come with a hefty price tag. And that means the practitioner must attempt to optimize fit and function for the moment, make adjustments over time if possible, and, ultimately, determine when a completely new device is necessary.

LER Pediatrics spoke with O&P experts on how to handle these issues, including how to accommodate growth without compromising fit and function.

While not a technical issue, patient and parent education is key to ensuring that everyone understands the purpose of a device and its projected longevity.

“We are always considering growth: How long can they wear it? What can we do to try to make it last longer?” said Leigh Davis, CPO, LPO, of Children’s Healthcare of Atlanta, and a board member of the American Academy of Orthotists and Prosthetists. “At the same time, since growth is so variable, you want to plan for what you see now rather than what might happen. You want to plan for care today versus planning for something that might happen in the future.”

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Growth spurts

Of course, all children grow, but as Davis pointed out, not all kids grow at the same rate, even during infant, toddler, and adolescent years, which are known for growth. And children who require O&P devices often have compromised skeletal systems and musculature because of their underlying diagnosis, and that may affect their growth schedule.

Tony Wickman, CTPO, chief executive officer of Freedom Fabrication in Havana, FL, noted that bones tend to grow faster linearly than they do circumferentially. Unlike in adults, in whom changes tend to be more global, changes in kids may happen in a piecemeal fashion. For instance, a child may experience linear growth of the feet rather than medial-lateral growth, but without any major growth in the rest of the lower limbs.

Davis agreed that linear growth is more of a concern in kids who may not build muscle mass as quickly as typically developing children.

“So you don’t often see a really large increase in calf circumference in kids with certain disabilities,” she explained. “But let’s say their ankle-malleolar width increases so much that it’s painful to put the brace on or they can’t even put it on at all. They’d have to come in so that we could make adjustments to the device.”

“Any presentation that requires an orthosis at that young an age requires a good fit even though these children aren’t ambulatory,” she said.

Many children who require O&P devices have underlying neurological conditions that can impact their ability to understand the purpose of the devices, use them properly, and express when the device is causing discomfort, possibly because of a change in body habitus.

Pirouz noted that standard clinical growth charts don’t really apply to kids who require devices, even if they don’t have underlying conditions.

“Even for typical kids, those charts are an aggregate. The chart will tell me where the child will be in a year, but it’s not going to tell me exactly when that will happen for each individual child. A week from now? Over the summer? That’s why follow-up is so important,” she said.

Finally, just as in the general population, childhood obesity is a problem in O&P patients. Pirouz pointed out that weight gain will most likely necessitate adjustments so that a device doesn’t pinch or dig into “redundant soft tissue.” But those adjustments don’t have to be complex.

“Whether it’s weight gain, or volume change that is part of the disease presentation, you can address that,” she said. “You can add a tongue to contain tissue. You can flare. You can pad. You can try interfaces to contain the tissue better.”

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Don’t fit for the future

It’s not worth trying to fit a device for potential growth because it will compromise fit in the here and now, experts agreed.

“I want the device as fitted as much as possible to the child’s current shape and size,” Wickman emphasized. “What I don’t like to see is a big, sloppy fit in hopes that the child will grow into it. Then you lose control of the fit and possibly compromise the device’s
efficacy.”

Davis concurred. For example, she said she wouldn’t typically build extra padding into an AFO that could be removed at a later time, because that can add bulk and compromise fit. She would leave the footplate a centimeter longer than the toes to accommodate for growth—but no longer, as that can cause problems with tripping or may require a shoe that’s a size too big. Footplate size can be misleading to parents as well, she said.

“A lot of parents will rely on the footplate as a measure of growth. So if they wait [to replace the device] until the toes are hanging all the way over the footplate, then the height of the AFO becomes a concern,” she said.

Pirouz agreed that achieving maximum fit and function in the present is paramount. Adjustments for growth can be made, but in the right context.

“For instance, with a night AFO, the patient is not ambulating, so you can make that footplate as long as you want in order to accommodate for growth,” she said. “But if you think about the height of the device, that can only be so tall, otherwise it may make the brace uncomfortable.”

Adjustments, add-ons, education

Adding that extra centimeter to a footplate is just one of many tactics practitioners use to maintain a quality fit while also accommodating for growth. But no single approach will work well for all children.

“You really have to look at the individual child and their diagnosis, their size, and their level of tolerance,” Davis said. “Is the weight of the device an issue for them? Is cosmesis an issue? Those sorts of things have to be taken into consideration.”

Wickman also cited diagnosis as a driving factor.

“With a diagnosis that’s relatively easy to manage, like genu valgum at the knee, that takes relatively gross pressures to manage and can be done with a minimum of contact,” he explained. “So in circumstances like that, it’s quite easy to manage for growth. The less surface that you have touching the patient, the more room you have for growth.”

But treating a condition like clubfoot is another matter, because the volume and circumference of the orthoses have to be managed in addition to the length, he added.

LER asked the O&P specialists specifically about a number of common techniques.

Leaving room to grow

Again, no one advocated a compromised fit for future growth. As Davis mentioned, she may leave a bit of room on an AFO footplate, but not at the top of the brace as it would hinder the child’s ability to bend their legs. Building extra width or circumference into a device also may compromise that device’s ability to control movement.

“Most of the kids are going to have pretty serious frontal plane involvement, so you need to be able to control supramalleolarly,” Davis said.

Infants grow very quickly so leaving room to grow can be tricky, Wickman said.

“There’s an old adage in O&P about growth adjustment: ‘The more you need, the less you can have.’ Very small children are going to need a lot of growth adjustment, but if they are smaller, then we can’t build in a lot for growth because achieving the best fit doesn’t give us a lot of room to work with,” he said.

Pirouz noted that pediatric devices generally don’t encapsulate the entire limb so allowances for growth can be made. This may mean using different interfaces to gain the best fit or using different tensions on the straps.

Adding toe pads or removable liners

Davis and Pirouz said they did not use removable liners because of the bulk they add, but have used toe pads to increase the length of a device.

Wickman acknowledged that removable liners can allow for extended device use in a growing child, but agreed that the added bulk and weight may not be desirable. Instead, he recommended using spot pads to cushion the bony prominences without adding bulk./td>

Heating/flaring to increase volume

Increasing volume by heating is a go-to protocol for making adjustments, Wickman said, and today’s thermoplastic materials can withstand heating if the circumference of the device needs to be increased. Another benefit of using spot pads rather than full liners is that the latter can get in the way of heating the device, he said.

Davis also supports heating to increase or decrease the circumference of a device, but she cautioned that doing so will also change the depth of the device in ways that could compromise its effectiveness.

“If I heat it out and it makes [the device] wider, it’s not as deep as it used to be,” she said.

Pirouz pointed out that it’s easier to maintain depth when decreasing the volume of a device than when increasing it.

“You can just cut the plastic away and maintain the depth,” she said. “If you are trying to increase the volume, then you will get a shallower device. As the calf portion of the AFO gets shallower from widening it [with heating], you can add a foam tongue to address that problem to match the volume of the device to the patient.”

Screwed-on joints vs internal or riveted joints

In general, Davis advised positioning screwed-on joints on the outside of the device so the practitioner has the option to move the proximal section superiorly.

With knee AFOs (KAFOs), she said she aims to build in the capability to bring the knee joint up for growth, whether that’s with Chicago screws or an attach plate.

“In either case, you can do growth adjustments, although the attach plate will add a lot of thickness,” Davis said. “We don’t do attach plates very often. More often, we move the holes and re-rivet or re-Chicago screw it.”

The use of growth adjustment bars will depend on the size of the child and how much weight he or she can tolerate, she added.

“If it’s a very small child, that may be more than they can handle,” Davis said. “Now, if it’s an adolescent, then a growth adjustment bar is probably a good idea. They have a lot of growth at that age, plus they are a bit bigger so that extra weight isn’t going to be that big a deal.”

In terms of adjustment bars, Wickman recommended stainless steel over aluminum as the former offers lighter weight but better durability, especially because active kids can be particularly rough on their devices. Stainless steel also will handle the stresses from repeated bending forces, for example in devices for genu varum or genu valgum, he said.

Pirouz said her group has not had any problems with internal joints, though she conceded that “you do have to extend your build-up to accommodate for that growth where the malleolae are going to move proximally.”

Prefab vs custom

The use of off-the-shelf (OTS), or prefabricated, devices may seem like an attractive option for growing children simply because they are less expensive than custom devices. But other factors also come into play.

Davis said her group does not use OTS devices very often in their pediatric population, in part because, in their experience, OTS devices aren’t always effective in kids who have triplanar deformities.

For Pirouz, whether a device is OTS or custom is less of an issue than its material construction.

“I think being able to make adjustments is the key, and some prefab devices allow you to do that while others don’t. It’s the same with some custom devices,” she explained. “Let’s say you have a custom carbon AFO that is laminated. Unless you build in padding that you can grind out, you really don’t have a lot of room to adjust that device.”

On the other hand, an OTS carbon AFO may have such a low profile, and such limited contact with the anatomy, that it can accommodate circumferential or linear growth, Pirouz said.

“Sometimes the referring specialist will just assume that a prefab device won’t work, and that’s not necessarily true,” she said.

Education

While it’s not a technical issue, patient and parent education is key to ensuring that everyone understands the purpose of a device and its projected longevity.

“A huge component of accommodating for growth is education—making sure the patient and the parents know what the device should look like when it’s properly fitted and when it may be time to come in for adjustments,” Pirouz stressed.

Pirouz said she and her colleagues start with very short follow-up periods of one to two weeks to establish compliance and a schedule for wearing the device. After that, follow-up appointments are scheduled every one to three months, depending on the child’s age.

“We always explain that we are shooting for the brace to last a year, but the priority is fit and function, so there is a chance that a new brace might be needed sooner,” she cautioned.

Davis makes sure to take measurements every time the patient comes for a follow-up visit so, should a new brace be necessary, she’ll have the data to back up that request.

“A lot of insurance companies will replace the device if there’s documented physiologic change,” she said. “So, let’s say the patient has gained ten pounds; that can be a valid justification to get a new brace.”

It also can be reassuring to parents who are concerned about the cost of replacing a device sooner rather than later.

On the other hand, practitioners may also find themselves contending with parents who will insist on a new device on a regular basis, especially if they believe that a newer device will work better and faster. Pirouz said that scenario is one she encounters more often than parents who are reluctant to get a new device. But if the desired clinical results are seen during regular follow-up, she said, then there may not be a need to jump immediately to a new brace.